Effects of conservation tillage with straw mulching on soil phosphorus components in the Loess Plateau
To explore the impact of straw mulching conservation tillage on the soil phosphorus composition and alkaline phosphatase pho D gene in the Loess Plateau,this study used the research platform of the Changwu Loess Plateau Agricultural Ecological Experiment Station,President of Chinese Sciences in Changwu County,Xianyang City,Shaanxi Province.Four treatments were set up:uncovered(CK),high straw coverage(St90)every July,August,and September,low straw coverage(S45)throughout the growth period,and high straw coverage(S90)throughout the growth period.The basic physical and chemical properties,the soil phosphorus,total organic phosphorus components,total inorganic phosphorus components,and number of copies of alkaline phosphatase pho D genes,and their impact mechanisms in the 0-20 cm topsoil layer under different straw mulching modes were studied.The results showed that,with the same coverage time,the contents of total phosphorus(TP),available phosphorus(AP),inorganic phosphorus,Ca2-P,and moderately labile organic phosphorus(MLOP)increased significantly with the increase in the coverage amount;Ca10-P was the main inorganic phosphorus component,accounting for 66.03％-72.34％,while MLOP was the main organic phosphorus component,accounting for 70.70％-78.23％.Straw mulching significantly increased the proportion of effective phosphorus source Ca2-P in inorganic phosphorus,while there was no significant change in the proportion of the other components in inorganic phosphorus and the proportion of organic phosphorus components.Short-term mulching before and after sowing was more beneficial to microbial metabolism than long-term mulching throughout the year,thereby accelerating the synthesis of soil organic phosphorus.The inorganic phosphorus content of soil under different straw mulching treatments ranged from 985.33 mg·kg-1 to 1043.33 mg·kg-1,which was significantly higher than that of organic phosphorus.Redundancy analysis showed that the soil pH,total carbon(TC),soil organic carbon(SOC),and soil water content(SWC)were negatively correlated with the MLOP content,while they were positively correlated with highly stable organic phosphorus(HSOP).Ca2-P was positively correlated with SWC,SOC,pH,and TP.Ca10-P was positively correlated with pH and NH4+-N.Straw mulching could increase the copy number of the alkaline phosphatase pho D gene,but the superposition of the full growth period mulching and high amount of straw mulching could inhibit the production of the alkaline phosphatase pho D gene.Straw mulching could significantly change the contents of organic phosphorus components,and high straw mulching significantly increased the content of inorganic phosphorus components,such as Ca2-P,throughout the growth period.The changes in the contents of soil organic and inorganic phosphorus components were most affected by soil TC and pH.
万方数据
维普
